1. Field of the Invention
The present invention relates to printers, print heads, and print head manufacturing methods. The present invention can be applied to a printer in which ink contained in ink cells is heated by heating elements so that ink drops are ejected from the ink cells.
2. Description of the Related Art
In ink jet printers, images, characters, etc., are printed by ejecting ink drops from small nozzles which then adhere to a print medium. In such ink jet printers, ink drops are ejected from small nozzles by heating ink with heating elements or by driving piezoelectric elements.
With respect to ink jet printers in which the ink drops are ejected by heating ink, a method of forming ink cells and nozzles on a substrate has been suggested in Japanese Unexamined Patent Application Publication No. 9-76516. According to this method, projecting objects having a predetermined shape are formed on the substrate at positions above heaters. Then, a setting resin is applied on the substrate and is set, and then the projecting objects are removed so that hollow parts are formed.
More specifically, in this method, heaters are first formed on a semiconductor substrate using semiconductor manufacturing techniques. Then, the projecting objects having the predetermined shape are formed above the heaters using photolithography techniques. The shape of the projecting objects is determined by the required shape of the hollow parts including the ink cells and the nozzles. Then, a setting resin such as epoxy resin, etc., is applied on the semiconductor substrate and is set. Then, the setting resin is partly removed so as to reveal the tip portions of the projecting objects, and then the projecting object are removed by dissolving them. Thus, hollow parts surrounded by the setting resin are formed, and ink passages, ink cells, and nozzles are formed on the semiconductor substrate. According to this method, the ink cells, etc., can be formed by simple processes.
However, in this method, there is a problem in that the nozzles cannot be formed with satisfactory precision.
In this method, the setting resin must be partly removed so as to reveal the tip portions of the projecting objects. However, in an etching process, which is a process for removing the setting resin, it takes approximately an hour to etch 10 μm. Accordingly, there is a problem in that a relatively long processing time is required. In addition, there is another problem in that side walls of ink outlets at the tips of the nozzles easily break, so that the ink drops may be ejected in different directions. In contrast, in barrel finishing, the setting resin can be partly removed and the tip portions of the projecting objects can be revealed in a relatively short time. However, in this case, since a large amount of side etching occurs, there is a problem in that the precision of the ink outlets at the tips of the nozzles is degraded.